Stabilized aqueous slurry blasting agent and process



United States Patent Ofi ice 3,235,423 Patented Feb. 15,1966

3,235,423 STABILIZED AQUEOUS SLURRY BLASTING AGENT AND PRGCESS John D. Ferguson, Rockaway, N.J., assignor to Hercules Powder Company, Wilmington, DeL, a corporation of as a freezing point depressant and has been employed in formulating compositions likely to be used under freezing temperature conditions. However, at best, the eutectic point for the three-component system is such that the Delaware slurry freezes at about 14 F. Accordingly, a principal N0 Drawing Filed Mar. 24 1964, 354,447 object of the present invention is to provide gelled aqueous m i blasting agents containing aluminum which are remark- T his invention relates to a novel aqueous slurry blastably t m over long pfinods storage.a.nd m addmon ing agent and to a method for its preparation More pap are utlllzable under temperature conditions heretofore ticularly, the present invention relates to a gelled aqueous 10 deemed m0 10W impractical P Slurry blasting agent having improved proparfies in Still another ob ect of the lnventlon IS tO provide a spect to Stability when particulate aluminum is Present process for manufacture of the aforementioned blasting The art for the manufacture of gelled aqueous slurry agents in a facile n economical manner wherein the explosives or blasting agents is well known Also, it is solid ingredients of the compositions are intimately inwell Known that gelled aqueous slurries containing alumi corporated f i .P num present problems in respect to stability in storage. Other Objects of the mverlmor} W111 tPPear herenlafier Gened aluminized aqueous slurries at normal Storage the novel features and comblnatl-ons belng set forth 1n the (80 F.) and elevated temperatures (120 F.) begin to appended clalms' deteriorate after Several days The gel begins to break Generallydescrlbed, the present invention contemplates down, syneresis occurs (exuding of water from the gel), the pnf'garanon d t l l Slurry blastmg agept and gassing occurs until after a short time, the gel is com- Fompnsmg a iensltlzmg agent; an morgamc mtrate oxldlz' pletely broken, and the ingredients become segregated. mg Salt; pamculate alummum; guar gum gFlhng agmt; Thus, it is necessary to inhibit the aluminum with chemi- Water; and not more F1 about 18% Welght of ethyl cal stabilizers, and, for example, phosphate inhibitors emene glycol as a Stablhzer P of from about 5 to ployed in small amount have been found useful for this about 7 for the l f i purpose. Moreover, it is known to formulate aqueous I examples glven the following table Will Serve l i t b tt accommodate l temperature ili b to lllustrate the compositions of the invention as Well as balancing water, ammonium nitrate and sodium nitrate method of Preparation All Parts and Percentages in a three-component system. Sodium nitrate is known ar by W ight.

Table Example '1 2 3 4 5 6 7 s Water percent 21. 0 21. 0 16. 0 16. 0 18. 0 20. 0 16. 0 15. 0 Smokeless Powder:

1.1" Sgle. Base B 30. 0 30. 0 35. 0 mm. Sgle. Base 25.0 25.0 35.0 20 mm. Sgle. Base m--. 35. 0 TNT all through 20 mesh. 20. 0 Ammonium Nitrate:

Prills 19.3 17.1 15.0 24.3 Grained B 38. 1 30. 2 15. 9 8. 9 Sodium Nitrate:

Fine 9.0 7.0 14.8 8.0 8.0 Coarses 16.0 14.3 15.3 Guar Gum 0.6 0.5 1 1.3 1 2 0.8 (k) 0.4 1.0 1.0 Aluminum 1 14. 0 18. 0 14. 0 14. 0 1s. 0 14. 0 14. 0 Pine Oil 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ethylene Glycol 4.0 3.9 1.5 1.5 3.7 I 4.5 10.0 18.0 Acetic Acid-.. trace trace trace trace trace trace trace trace pH 4.8 5.2 5.8 6.0 0.0 5.4 0.0 6.6 Density (gm./cc.) 1.44 1.43 1.42 1. 46 1.47 1.41 1.4 1.4 Shooting Results (3 x 28 pipe under water) m./ 500.!

160 gm. booster m gm. booster 40 gm. booster m 20 gm. booster 10 gm. booster Approx. Freezing Point, Resutsalsung:

Mixing Procedure (num- (1) Add water, Pine Oil bered stepwise).

Glycol; (2) Pregel A Guar Gum with small amt. ingredients1 to 2 minutes; (3) Add ingredients and Guar Gum; (4) Add Smokeless Powder Alum. (adjust pH to 5.5 w./acid).

Mixing Pro- (1) Add water, (1) Add water, Glycol,

a Length 0.1, width 0.04, perforationm-l.

' Length 0.1", width 0.12, pel'forations-7.

0 Length 0.3", width 0.08, perforations-1.

d All on 20 mesh.

0 5% 011 mesh (contains 0.11% zinc oxide) i 7% on 20 mesh. 1

g All on 20 mesh.

99% through 60 mesh.

1 Inhibited (j), Self-complexrng.

i Inhibited, self-complexing.

k Noninhibited, nonself-complexing.

1 All through 5 mesh.

m 59.5 RDX, 39.5 TNT, 1.0 wax.

n PETN.

Stored 6 wks. at F.n0 sign of deterioration. Soft and flowable at 40 after 36 hours.

q Soft and fiowable at 60 F. after 36 hours.

With reference to the foregoing table, it will be seen that the aluminized products were remarkably stable and, in addition, were adjustable to accommodate extremely low temperature requirements. Also, it will be seen that in preparation of the products, a viscous sol of guar gum gelling agent, water and ethylene glycol was first formed, that practically all the particulate solid blasting ingredients including the aluminum were suspended therein and that the final blasting agent composition was controlled to have a pH of from about 5 to about 7 by ingredient selection, by in process adjustment of pH, by end product adjustment of pH or a combination of these procedures. The pine oil was added as a defoamer to increase the density of the composition, and the initial addition of a small amount of the solid ingredients in the mix served to aid in dispersing the guar gum and prevent lumping.

Moreover, with reference to the table, the physical nature and consistency of the blasting agents set forth will vary somewhat depending upon the precise formulation in each instance. This, of course, is generally advantageous since it permits tailoring of the compositions to fit conditions for use in the field. It will be appreciated that field conditions may dictate the addition of ingredients such as sulfur, ferrosilicon, ferrophosphorous and the like, which are well known in the art and contemplated within the purview of the invention. Generally speaking, however, aqueous slurry blasting agents in accordance with the prior art become quite firm and lose their flow properties at about F. and tend to freeze at temperatures about -l4 F. In contrast thereto, the gelled aqueous slurry blasting agents according to the invention may be formulated to retain their flow properties at temperatures as low as 60 F. and as Example 8 demonstrates, the composition containing 18% ethylene glycol was soft and flowable and not frozen after 36 hours storage at 60 F. Also, as Example 4 demonstrates, the blasting agent of the invention after being stored for six weeks at 120 F. showed no sign of deterioration. In all instances, extremely stable products were obtained.

The sensitizing agents which may be used in accordance with the present invention include smokeless 'powder, TNT, RDX, PETN, Pentolite, Cyclotol, HBX and the like. These materials may be pelleted, flaked or grained.

The inorganic nitrate oxidizing salt is ammonium nitrate and/or sodium nitrate, which are used as strength and/or oxygen donors for the compositions. The salts are used in an amount of from about 10 to about 50 percent and from about to about 30 percent and preferably from about to about 40 percent and preferably from about 5 to about percent, respectively.

The guar gum is a galactomannan substance and may be of the inhibited or uninhibited, and self-complexing, types with the gum present in an amount of from about 0.2 to about 5% and preferably from about 0.2 to about 2%.

The water content of the compositions is important in determining the consistency, the amount of solution in the formula (which controls freezing characteristics), and the amount of ethylene glycol to be added to the composition. Consistency of the product is important for economical packaging, and for proper use of the slurry in blasting. The softness of consistency is greatly dependent on the solid to liquid ratio, and, therefore, the percent water in the mix. present may be from about 8 to about and preferably from about 10 to about 25%.

For proper functioning of ethylene glycol in its additional role as a freezing point depressant, it is generally used in an amount of about 9% of the ammonium nitrate/sodium nitrate/water solution in the mix. This percentage forms the optimum system for consistency, effect of ethylene glycol on the gelation of the guar gum,

The amount of water land the explosive energy. Preferably, however, the ethylene glycol is utilized in an amount of from about 1 to about 5%. Ethylene glycol has been used, however, in amounts up to 18% where extremely low temperatures are to be accommodated as shown in the examples.

The percentage of aluminum use-d is determined by the strength desired in the ultimate composition. The aluminum may be varied in amount from about 2 to about 40%, and preferably is present in an amount of from about 5 to about 20% The pH of the compositions is adjusted with acid when necessary. For this purpose, acetic acid or nitric acid are generally used, but other acids and butter salts can be used. A pH of from about 5 to about 7 has been found essential to obtain stability over long periods of storage for the compositions of this invention.

The method of addition of ingredients is set forth in the table. The most important steps in the procedure are the initial addition of guar gum and the time of addition of the ethylene glycol. 'A portion ofthe guar gum should be added to the water and hydrated before the solid ingredients are added. This forms a sol of sufficient viscosity to suspend the solid ingredients. Ethylene glycol consistently should be added before the salts so that proper dispersal of the ethylene glycol in water will take place.

The advantages of the invention are multifold. The ethylene glycol stabilizes the aluminized compositions for extended periods of storage at elevated temperatures and at ambient temperatures. For example, the composition of Example 2 has been in storage for one year at ambient temperatures without any sign of deterioration. Furthermore, the presence of ethylene glycol lowers the freezing point of the compositions with the additional advantage of being able to utilize substantial amounts of the glycol without disrupting the stability characteristics of the compositions. Thus, soft, usable products at temperatures as low as 60 F. are obtainable. Still further, ethylene glycol used with guar gum does not inhibit its gelation characteristics and can be used as a dispersing agent for the guar gum. This gives a homogeneous mixing of the guar gum without lumping, which is quite advantageous for mixing of the ingredients.

It will be seen, therefore, that this invention may be carried out by the use of various modifications and changes without departing from its spirit and scope with only such limitations placed thereon as are imposed by the appended claims.

What I claim and desire to protect by Letters Patent is:

1. A gelled aqueous slurry blasting agent comprising (a) a sensitizing agent;

(b) an inorganic nitrate oxidizing salt;

(c) from about 2 to about 40% of particulate aluminum;

(d) guar gum gelling agent;

(e) water; and

(f) from about 1 to about 18% by weight of ethylene glycol as a stabilizer at a pH of from about 5 to about 7 for the final blasting agent.

2. A gelled aqueous slurry blasting agent comprising by weight (a) from about 10 to about 40% of a sensitizing agent;

(b) from about 10 to about 50% of ammonium nitrate;

(c) from about 5 to about 30% of sodium nitrate;

(d) from about 0.2 to about 5% of guar gum gelling agent;

(e) from about 2 to about 40% of particulate aluminum;

(f) from about 8 to about 30% of water; and

(g) from about 1 to about 5% of ethylene glycol as a stabilizer at a pH of from about 5 to about 7 for the final blasting agent composition.

3. A gelled aqueous slurry blasting agent comprising by weight (a)-from about 20 to about 40% of a sensitizing agent;

(b). from about to about 40% of ammonium nitrate;

(c) from about 5 to about 20% of sodium nitrate;

(d) from about 0.2 to about 2% of guar gum gelling agent (e) from about 5 to about 20% of particulate aluminum;

(f) from about 10 to about 25% of water; and

(g) from about 1 to about 5% of ethylene glycol as a stabilizer at a pH of from about 5 to about 7 for the final blasting agent composition.

4. The gelled aqueous slurry blasting agent of claim 2 in whichlthe sensitizing agent is smokeless powder.

5. The gelled aqueous slurry blasting agent of claim 2 in which the sensitizing agent is TNT.

6. The gelled aqueous slurry blasting agent of claim 3 in which the sensitizing agent is smokeless powder.

7. The gelled aqueous slurry blasting agent of claim 3 in which the sensitizing agent is TNT.

8. In'the process of manufacturing a stable aqueous slurry blasting agent containing aluminum, the improvement which comprises 9. In the process of manufacturing a stable aqueous slurry blasting agent containing aluminum, the improvement which comprises (a) forming a viscous sol of guar gum gelling agent,

5 water and ethylene glycol,

(b) suspending a sensitizing agent, an inorganic nitrate oxidizing salt and particulate aluminum in the viscous sol; and

(c) controlling the pH to obtain a pH of from about 5 to about 7 for the final composition.

10. In the process of manufacturing a stable aqueous slurry blasting agent containing aluminum, the improvement which comprises (a) forming a viscous sol of guar gum gelling agent,

water and ethylene glycol,

(b) suspending a sensitizing agent, ammonium nitrate, sodium nitrate and particulate aluminum in the viscous sol; and

(c) controlling the pH to obtain a pH of from about 5 to about 7 for the final composition.

LEON D. ROSDOL, Primary Examiner. BENJAMIN R. PADGETT, Examiner. 

2. A GELLED AQUEOUS SLURRY BLASTING AGENT COMPRISING BY WEIGHT (A) FROM ABOUT 10 TO ABOUT 40% OF A SENSITIZING AGENT; (B) FROM ABOUT 10 TO ABOUT 50% OF AMMONIUM NITRATE; (C) FROM ABOUT 5 TO ABOUT 30% OF SODIUM NITRATE; (D) FROM ABOUT 0.2 TO ABOUT 5% OF GUAR GUM GELLING AGENT; (E) FROM ABOUT 2 TO ABOUT 40% OF PARTICULATE ALUMINUM; (F) FROM ABOUT 8 TO ABOUT 30% OF WATER; AND (G) FROM ABOUT 1 TO ABOUT 5% OF ETHYLENE GLYCOL AS A STABILIZER AT A PH OF FROM ABOUT 5 TO ABOUT 7 FOR THE FINAL BLASTING AGENT COMPOSITION. 